Field of the Invention
The present invention is directed to a device, system and method for the visual alignment of a pipettor tip and a reference point marker. The invention also relates to a use of the device.
Brief Description of the Related Art
In order to precisely access positions in an automated analyser system, such as a robotic pipetting system, the location of the positions has to be trained at least on a first set-up of the pipetting system. Usually the process has to be repeated upon any intervention that can lead to a shift of positions.
The current standard procedure is to access a number of reference point marker positions with the robotic pipetting system either via manual movement commands or via automated detection of the reference point marker position by measuring the capacity between pipettor tip or pipettor needle and reference point marker or by measuring the motor current of the z-axis drive to detect a collision of pipettor needle and reference point marker.
In case of manual movement, the analyser system and the reference point marker positions are aligned by the operator usually by visual means.
By determining some (usually 2 or 3) reference point marker coordinates in analyser system coordinates it is possible to interpolate coordinates in an area framed by the reference point markers.
The pipettor tip and the reference point marker have to be aligned in three dimensions, x-, y- and z-direction.
U.S. Pat. No. 5,195,234 discloses an apparatus for visually aligning parts for placement using one camera that comprises a device for picking and placing a part on an object, a device for moving and removing optics into and out of a work envelope having the object, a device for locating landmarks on the object within the work envelope, and a device for aligning the part with the landmark in the work envelope.
In U.S. Patent Application Publication No. 2012/065912 A1 an apparatus is disclosed that includes a calibration member, an imaging device and a proximity sensor. The calibration member is configured to be removably coupled to a deck of a liquid handling system. The calibration member has an alignment portion configured to matingly engage a portion of the deck such that a position of the calibration member is fixed with respect to the deck. The imaging device is coupled to the calibration member such that an axis of a lens of the imaging device intersects the deck at a first predetermined location relative to a deck reference point in at least a first dimension and a second dimension. The proximity sensor is coupled to the calibration member such that a calibration reference point on the proximity sensor is at a second predetermined location relative to the deck reference point in a third dimension.
U.S. Pat. No. 6,359,694 B1 a device and method for detecting the position of components and/or for checking the position of terminals of components is described. An insertion head with such a device for detecting the position of components and/or for checking the position of terminals of components is further disclosed, the components are illuminated with vertically incident light, with multi-directional, obliquely incident light, and with horizontally incident light, so that the side surfaces of the components, and thus the projecting terminals as well are sufficiently illuminated. For the horizontal illumination, a light deflection element is employed wherein light is emitted by a light source into the light deflection element, is reflected at a first outer wall of the light deflection element, and is directed into an opening of the light deflection element in which the component is disposed.
WO 2005/103656 A1 describes a multiple surface viewer that provides views of several surfaces of an object. Light is reflected onto a beam splitter which reflects it towards a plurality of reflectors and onto a front surface of an object under inspection. The reflectors reflect the light onto side surfaces of the object. The image of the front surface is reflected back to the beam splitter, as are images of the side surfaces, via the reflectors. The various images pass through the beam splitter to a focusing lens, which focuses the composite image onto an image capture device. The multiple surface viewer captures images of multiple views of an object, without needing to rotate or flip the object
The visual alignment of the state of the art of the pipettor tip and the reference point marker has a number of disadvantages:                1) It is difficult for the user to align the pipettor tip and the reference point marker in a precise manner because the reference point markers are at different positions inside the analyser system.        2) Usually, at least one dimension (x, y or z) is not visible for the user due to neighbouring modules which are covering the reference point marker.        3) The user usually has to move to different positions within the analyser system in order to visually align the pipettor tip and the reference point marker in the different dimensions.        